Existing fluid generating devices are usually powered by a three phase motor. The three phase motor has a higher cost than the single phase brushless motor. However, the single phase motor has the problem of startup failure due to dead point. In order to avoid the dead point, the air gap between the stator and rotor of the single phase brushless motor is usually an uneven gap. However, the motor with uneven air gap usually has an unduly large cogging torque and hence large noise.
The present invention aims to provide a fluid generating device which can overcome the above problems.